• iOS 9: Go to Settings > Phone. Different options appear depending on your carrier.

  • If you see Wi-Fi calling, tap it, then turn Wi-Fi Calling on This iPhone on.

    After you turn on Wi-Fi calling, you may see an Add Wi-Fi Calling For Other Devices button. Tap it to allow calls using your other devices that aren’t on the same Wi-Fi network as your iPhone, or if your phone is off. Otherwise, you can still use your Mac to make phone calls, but your iPhone must be turned on and on the same Wi-Fi network as your Mac.

    Note: Only certain phone carriers support Wi-Fi calls for devices that are not on the same Wi-Fi network as your iPhone. For information, see the Apple Support article Make a call over Wi-Fi. You also need iPhone 5s, iPhone 5c, or later.

  • If you see Calls on Other Devices, tap it, then turn it on.

    This option allows calls using your other devices that are on the same Wi-Fi network as your iPhone.

• iOS 8: Go to Settings > FaceTime, then turn iPhone Cellular Calls on.

If you turn on Wi-Fi calls on your iPhone, when you open FaceTime on your Mac, onscreen instructions might appear to turn on Wi-Fi calls on your Mac. If you’re not asked, do the following.

1. Open FaceTime, then choose FaceTime > Preferences.

2. Select “Calls from iPhone.”

   If you don’t see this option, make sure your Mac meets all of the requirements above, then open FaceTime preferences again.

3. If an Upgrade to Wi-Fi Calling button appears, click it, then follow the onscreen instructions.

   This button appears if your carrier supports Wi-Fi calling when your iPhone is turned off or is on a different Wi-Fi network.

To turn off phone calls, deselect “Calls from iPhone.”

• From FaceTime: Enter a phone number in the search field, then click the Audio button or click Audio to see your past phone calls.

• From Contacts: Select a contact, move your pointer over a phone number, then click the Phone button .

• From Safari: Select a phone number in a webpage, click the pop-up menu , then choose the iPhone you want to use to make the call.

• From Mail: Place the pointer over a phone number in an email, click the pop-up menu , then choose the iPhone you want to use to make the call.

• From Maps: Click a place of interest, click the Info button , place your pointer over a phone number, then click the Phone button .

• From Spotlight: Enter the name of a person or place in the Spotlight search field, then select the matching search result. Move the pointer over a phone number, then click the Phone button .

• Accept an incoming call: Click Accept.

• Send a text message using iMessage: Click next to Decline, then choose Reply with Message.

• Create a reminder to call the person back: Click next to Decline, then choose Remind Me.

  

• Mute yourself: Click Mute.

  You can still hear the other person on the call.

• Answer automated phone system prompts: Click the phone call notification and enter numbers.

• Switch to a FaceTime video call: Click Video.

• Use call waiting: If you’re on a call, and a new phone call notification appears, click Hold & Accept. Click to switch between calls.

• Start a conference call when you have another call on hold: When you’re on a phone call and have another phone call on hold, click Merge.

• Transfer the call to your iPhone: When your Mac is near your iPhone, tap the Handoff icon that automatically appears in the bottom left of the lock screen of your iPhone, or click the Handoff icon that appears to the left of the Dock on your Mac.

  Depending on how you set up Wi-Fi calls, a “Touch to return to call” banner might appear at the top of the screen on your iPhone when unlocked.